1. Field of the Invention
The invention relates to techniques for indexing and searching for mixed media documents formed from at least two media types, and more particularly, to recognizing images and other data using multiple-index Mixed Media Reality (MMR) recognition that uses printed media in combination with electronic media to retrieve mixed media documents.
2. Background of the Invention
Document printing and copying technology has been used for many years in many contexts. By way of example, printers and copiers are used in commercial office environments, in home environments with personal computers, and in document printing and publishing service environments. However, printing and copying technology has not been thought of previously as a means to bridge the gap between static printed media (i.e., paper documents), and the “virtual world” of interactivity that includes the likes of digital communication, networking, information provision, advertising, entertainment and electronic commerce.
Printed media has been the primary source of communicating information, such as news papers and advertising information, for centuries. The advent and ever-increasing popularity of personal computers and personal electronic devices, such as personal digital assistant (PDA) devices and cellular telephones (e.g., cellular camera phones), over the past few years has expanded the concept of printed media by making it available in an electronically readable and searchable form and by introducing interactive multimedia capabilities, which are unparalleled by traditional printed media.
Unfortunately, a gap exists between the electronic multimedia-based world that is accessible electronically and the physical world of print media. For example, although almost everyone in the developed world has access to printed media and to electronic information on a daily basis, users of printed media and of personal electronic devices do not possess the tools and technology required to form a link between the two (i.e., for facilitating a mixed media document).
Moreover, there are particular advantageous attributes that conventional printed media provides such as tactile feel, no power requirements, and permanency for organization and storage, which are not provided with virtual or digital media. Likewise, there are particular advantageous attributes that conventional digital media provides such as portability (e.g., carried in storage of cell phone or laptop) and ease of transmission (e.g., email).
One particular problem is that a publisher cannot allow access to electronic versions of content using printed versions of the content. For example, for the publisher of a newspaper there is no mechanism that allows its users who receive the printed newspaper on a daily basis to use images of the newspaper to access the same online electronic content as well as augmented content. Moreover, while the publisher typically has the content for the daily newspaper in electronic form prior to printing, there currently does not exist a mechanism to easily migrate that content into an electronic form with augmented content.
A second problem in the prior art is that the image capture devices that are most prevalent and common as part of mobile computing devices (e.g., cell phones) produce low-quality images. In attempting to compare the low-quality images to pristine versions of printed documents, recognition is very difficult if not impossible. Thus there is a need for a method for recognizing low-quality images.
A third problem in the prior art is that the image recognition process is computationally very expensive and can require seconds if not minutes to accurately recognize the page and location of a pristine document from an input query image. This can especially be a problem with a large data set, for example, millions of pages of documents. Thus, there is a need for mechanisms to improve the speed in which recognition can be performed.
A fourth problem in the prior is that comparing low-quality images to a database of pristine images often produces a number of possible matches. Furthermore, when low-quality images are used as the query image, multiple different recognition algorithms may be required in order to produce any match. Currently the prior art does not have a mechanism to combine the recognition results into a single result that can be presented to the user.